1. Technical Field
The present invention relates to a package for a light-emitting device and, more particularly, to a package for a light-emitting device which provides white light by changing a wavelength of light emitted from the light-emitting device.
2. Description of the Related Art
Recently, a light-emitting device in which Al or In is added to GaN has been in the spotlight owing to a long lifespan, low power consumption, excellent brightness, and an eco-friendly element not harmful to the human body as compared with a conventional incandescent. In particular, a light-emitting device providing white light has been further in the spotlight.
The light-emitting device is being used in a vehicle illumination, a traffic signal lamp, and the Back Light Unit (BLU) of a liquid crystal display owing to the above-described advantages.
MacAdam's ellipse rule has recently been proposed as an index for evaluating whether a color coordinate measured at an artificial light source is identical with a color coordinate when being seen by an eye of a human being. MacAdam's ellipse rule provides a four-step criterion. Currently, in the United States, an artificial light source that does not comply with three steps of MacAdam's ellipse rule is not allowed to be sold. In order to satisfy the three steps of MacAdam's ellipse rule, it is very important to reduce a color variance in white light.
Meanwhile, Korean Patent Laid-Open Publication No. 10-2008-0070193 discloses a phosphor light emitting diode and a method for manufacturing the same. However, the invention disclosed in the Korean Patent Laid-Open Publication is problematic in that a phosphor film is deteriorated because the phosphor film is attached by a thermal printing process. It has been known that this problem has a great defect in reliability that is most important in a white light light-emitting device. Furthermore, there is a problem in that a light source phenomenon in which light emitted from the light-emitting device leaks because the phosphor film is attached to some regions of the light emission surface.